spare tyre 
noun
1An extra tyre carried in a motor vehicle for use in case of a puncture.By Feb. 23, at least 20 truck and car tires - including spare tires mounted on the front and back of trucks - had been pierced by a sharp instrument, possibly an ice pick....
- Take water and a spare tire, and make sure that someone back at the hotel knows if you're going to try to trek all the way to the Marine landing site.
- Check your spare tire and make sure you have one.
2 informal A roll of fat round a person’s waist.I set myself a program of losing weight and getting rid of the spare tyre around the waist....
- Men's health magazines, for example, repeatedly run exhortations containing ways to lose love handles and spare tires so their stomachs will come to resemble those featured prominently on every single self-esteem-battering cover.
- People with serious spare tires around their middle do win bowling tournaments.